Well, (and to state the obvious) - if you're doing it simply because you saw somebody else do it, or just heard that it was a "good idea", without really understanding why - then yeah, sure I'd say it's cargo cult.

But if you've read the book, absorbed and understood the information and then made an informed decision to do it (or not) - then it isn't. (or if you've made the same informed decision without even seeing the book)

However, "Best Practices" and "Cargo Cult" are not necessarily mutually exclusive terms (as your title might suggest). For example, I think most people would agree that it's good practice to always use strict and warnings. Yet, not everybody that does that will be able to tell you why it's a good practice - or perhaps more importantly - when it's okay to not do it. Does that mean that these people are "Cargo Culting"?